State Management in React with Recoil

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State management is a big part of our modern web applications. The need for a global state manager was felt since the beginning of React.

Then Redux came into the picture and won it. It has become the go-to state management solution for most large-scale applications.

But redux is far from perfect. And recently it seems that the popularity of redux is declining. Many new players have joined the game of state management and Recoil is one of them.

So what’s Recoil anyway?

Simply speaking Recoil is yet another state management solution for React. React community has jumped up after the introduction of RecoilJS. It has been gaining popularity at a very fast pace.

It is maintained by a team at Facebook (who are also the maintainer of React).

Although keep in mind that Recoil is not the official state management library for React.

Why should you care?

Recoil has some distinct benefits over other state management libraries

• It has fewer boilerplate (as opposed to redux)

• Easy to learn and understand (opposite to redux)

• Easy to understand the data flow (opposite to redux)

• More in line with modern React (support concurrent mode)

• Excellent developer experience

• Performance is not an issue

Lot’s of promises here. But is this library really that good? Let’s glance over the library itself to find out the answer!

Main Concepts of Recoil

Any State management library has 3 purposes mainly

1. Creating the state

2. Reading data from state

3. Updating the state

1. Creating the State

You can use 2 things to create a store in Recoil.

• Atom

• Selector

Let’s see how to use them.

1a. Atom

According to documentation

Atoms contain the source of truth for our application state

In simple terms, atoms are a piece of data that you want to store in the state. it can be the theme of your application or a list of todo.

const todoListState = atom({
  key: 'todoListState',
  default: [],
});

If you want some piece of your data to be stored and accessed globally you have to create an atom for that.

1b. Selector

According to do documentation

A selector represents a piece of derived state

That means if

• You want to derive some data from other states

• Or want to compute something based on the data stored in atoms

You can use selectors for this purpose. For example, you saved your todos in the todoListState atom. Now you want to filter the todoList based on their status. You can use a selector for that.

const filteredTodoListState = selector({
  key: 'filteredTodoListState',
  get: ({get}) => {
    const filter = get(todoListFilterState);
    const list = get(todoListState);

    switch (filter) {
      case 'Show Completed':
        return list.filter((item) => item.isComplete);
      case 'Show Uncompleted':
        return list.filter((item) => !item.isComplete);
      default:
        return list;
    }
  },
});

2. Read the Values

Recoil has provided us with some nice hooks. One of them is useRecoilValue which can be used to read the data from the atom or selector.

function TodoList() {

  const todoList = useRecoilValue(filteredTodoListState);

  return (
    <>
      {// render something based on todoList value}
    </>
  );
}

3. Update the values

One nice thing about Recoil is that it’s more Reactish.

We have useState hook in React. Recoil has provided us with a similar hook named useRecoilState . It can be used to set the state of the atom or selector.

function TodoList() {

  const [todos , setTodos] = useRecoilState(todoListState);

  useEffect(() => {
    setTodos()      // -> set the initial list of todos here
  }, [])

  return (
    <>
      {// render something based on todoList value}
    </>
  );
}

There are some other utilities that can help you in different scenarios. You can take a look at the documentation

Will it replace Redux?

The short answer is… NO! Let me explain

Recoil is not the solution for everything

Recoil is designed to solve a very specific problem. If you have lots and lots of inter-dependent components then it can help you to boost performance.

On the other hand, redux is more generic. It's not even specific to React.

Recoil is large in size

If you go to the NPM you can see the size of these packages.

recoil = 1.56 MB
redux+ react-redux = 448 Kb

So Recoil is significantly larger than the Redux. In many cases especially where bundle size is important this becomes an important issue.

Recoil is not ready… yet

Recoil is fairly new compared to redux. It’s being actively developed. But you can expect many unexpected hiccups along the way! It’s not considered production-ready yet.

But Redux is an established library with lots of other libraries to support it. Also, it’s more stable and has excellent support from the community.

Redux is getting better

Most of the issues are with the verbosity of Redux. The introduction of the redux toolkit has solved this problem too (Almost :p ).

And with strong community support and active development, it will get better day by day.

Many large projects already use Redux

Redux is not going anywhere. At least not for the next 2–3 years. Many large projects are already being run using redux and it’s hard to change the architecture overnight.

So if you are targeting for a job more often than not Redux will be more desirable on your resume!

Recoil does not have middleware support

Currently, Recoil does not support middlewares. Maybe it will come in the future. But I think you should consider this before adopting.

So should you learn Recoil?

Absolutely yes!

It has introduced some new interesting concepts. Maybe try this out for some fun little project. Play with it. Know when this can be useful. If your project requires it then use it.

Most importantly, keep learning! Have a great day!

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